1. Field of the Invention
The present invention relates to regulators for underwater breathing apparatus and more particularly to an inlet valve for second stage regulators.
2. Description of the Prior Art
In a typical underwater breathing apparatus, air or other breathable gas is supplied to a diver from a high pressure tank via a two-stage regulating system. The regulator first stage is mounted to the high pressure tank valve and functions to reduce tank gas pressure to about 150 psi above ambient pressure. The tank and regulator first stage are carried by the diver on his back. A flexible hose conduit supplies the reduced pressure gas to a regulator second stage held by the diver in his mouth with a mouthpiece. The second stage is a demand regulating device which opens to supply the diver's mouth breathing gas in response to inhalation effort. Provision is also made to exhaust exhaled gas through the mouthpiece out into the water.
For convenience and safety, the diver opens the pressure tank valve prior to entering the water. Once the tank is mounted on the diver's back, it is very difficult for the diver to manipulate the tank valve himself. As a consequence, the diver usually leaves the gas supply valve open, even when not breathing through the regulator, for example, when snorkeling on the water surface. Unfortunately, the unattended regulator tends to free flow with a resultant waste of gas whenever water surges against the regulator second stage or it is otherwise jolted. To date, there is not a convenient and safe method for the diver to open or close his gas supply after the tank supply valve is opened and the system is mounted on his back.
The present invention solves the problem by providing a shut-off means which is conveniently mounted at the inlet to the regulator second stage.